Millisecond Forums

Thank you very much for your prompt reply.
Would you mind helping me with one more question?
Since the practice trials have three levels, I want to change the show time of each level. For example, for N=1, show time is 500ms, for N=2, show time is 1000ms and 2000ms for N=3. I was wondering that I need to define more trials, right?
Thank you very much again!

No, you don't necessarily need to define additional <trial> elements. You can change

<trial nontarget>
/ stimulustimes = [0 = nontargetshape; 500 = eraser]
...
</trial>

to

<trial nontarget>
/ ontrialbegin = [if (values.N==1) trial.nontarget.insertstimulustime(shape.eraser, 500)]
/ ontrialbegin = [if (values.N==2) trial.nontarget.insertstimulustime(shape.eraser, 1000)]
/ ontrialbegin = [if (values.N==3) trial.nontarget.insertstimulustime(shape.eraser, 2000)]
/ ontrialend = [trial.nontarget.resetstimulusframes()]
/ stimulustimes = [0 = nontargetshape]
...
</trial>

to achieve different display durations depending on the N-level. (Do the same for the target trials.)

Thank you very much! But the trialduration is always the same. I just want it to be 500ms, 1000ms or 2000ms. However, if I delete the trialduration, it doesn't run at all....

*start trial runs N-times (unless N = 0, then it runs N = 1 time)
<trial start>
/ ontrialbegin = [if (values.N==1) trial.start.insertstimulustime(shape.eraser, 500)]
/ ontrialbegin = [if (values.N==2) trial.start.insertstimulustime(shape.eraser, 1000)]
/ ontrialbegin = [if (values.N==3) trial.start.insertstimulustime(shape.eraser, 2000)]
/ ontrialend = [trial.start.resetstimulusframes()]
/ stimulustimes = [0 = startshape]
/ validresponse = (noresponse, 30)
/ correctresponse = (noresponse)
/ ontrialbegin = [
{if (values.N == 1) values.currenttarget = values.minus1};
{if (values.N == 2) values.currenttarget = values.minus2};
{if (values.N == 3) values.currenttarget = values.minus3};
{if (values.N == 4) values.currenttarget = values.minus4};
values.starttrialcounter += 1;
]
/ ontrialend = [
{if (values.N == 0) values.currenttarget = picture.startshape.currentitemnumber};
values.minus4 = values.minus3;
values.minus3 = values.minus2;
values.minus2 = values.minus1;
values.minus1 = picture.startshape.currentitemnumber
]
/ responsetime = 0
/trialduration = 3000
/branch = [if (values.starttrialcounter < values.N) trial.start]
</trial>


<trial nontarget>
/ ontrialbegin = [if (values.N==1) trial.nontarget.insertstimulustime(shape.eraser, 500)]
/ ontrialbegin = [if (values.N==2) trial.nontarget.insertstimulustime(shape.eraser, 1000)]
/ ontrialbegin = [if (values.N==3) trial.nontarget.insertstimulustime(shape.eraser, 2000)]
/ ontrialend = [trial.nontarget.resetstimulusframes()]
/ stimulustimes = [0 = nontargetshape]
/validresponse = (noresponse, 30)
/ correctresponse = (noresponse)
/ ontrialbegin = [
{if (values.N == 1) values.currenttarget = values.minus1};
{if (values.N == 2) values.currenttarget = values.minus2};
{if (values.N == 3) values.currenttarget = values.minus3};
{if (values.N == 4) values.currenttarget = values.minus4}
]
/ ontrialend = [
values.minus4 = values.minus3;
values.minus3 = values.minus2;
values.minus2 = values.minus1;
values.minus1 = picture.nontargetshape.currentitemnumber;
values.CorrReject = values.CorrReject + trial.nontarget.correct;
values.FalseA = values.FalseA + trial.nontarget.error;
values.TotalFA = values.TotalFA + trial.nontarget.error;
values.DV = (values.TotalHits - values.TotalFA)/values.TotalBlocks;

]
/ responsetime = 0
/ trialduration = 3000
</trial>


**if target, press the letter "A" (code: 30)
<trial target>
/ ontrialbegin = [if (values.N==1) trial.target.insertstimulustime(shape.eraser, 500)]
/ ontrialbegin = [if (values.N==2) trial.target.insertstimulustime(shape.eraser, 1000)]
/ ontrialbegin = [if (values.N==3) trial.target.insertstimulustime(shape.eraser, 2000)]
/ ontrialend = [trial.target.resetstimulusframes()]
/ stimulustimes = [0 = targetshape]
/validresponse = (noresponse, 30)
/ correctresponse = (30)
/ ontrialbegin = [
{if (values.N == 1) values.currenttarget = values.minus1};
{if (values.N == 2) values.currenttarget = values.minus2};
{if (values.N == 3) values.currenttarget = values.minus3};
{if (values.N == 4) values.currenttarget = values.minus4};
]
/ ontrialend = [
values.minus4 = values.minus3;
values.minus3 = values.minus2;
values.minus2 = values.minus1;
values.minus1 = picture.targetshape.currentitemnumber;
values.Hits = values.Hits+ trial.target.correct;
values.Misses = values.Misses + trial.target.error;
values.TotalHits = values.TotalHits + trial.target.correct;
values.DV = (values.TotalHits - values.TotalFA)/values.TotalBlocks;
]
/ responsetime = 0
/ trialduration = 3000

You need to distinguish between two different things:

#1 is the display duration of the target or non-target stimulus. In the original that's hardcoded to 500ms:

<trial nontarget>
/ stimulustimes = [0 = nontargetshape; 500 = eraser]
...
</trial>

nontargetshape is displayed at t0 and is overwritten by <shape eraser> 500ms later.

#2 is the <trial> element's *overall* duration, which is *unrelated* to #1 above and fixed at 3000ms in the original:

<trial nontarget>
...
/trialduration = 3000
</trial>

If you want to vary that depending on the N-level, you need to introduce a new <values> entry

<values>
...
/ mytrialduration = 500
...
</values>

and set values.mytrialduration to the desired value depending on N-level:

<trial nontarget>
/ ontrialbegin = [if (values.N==1) values.mytrialduration = 500]
/ ontrialbegin = [if (values.N==2) values.mytrialduration = 1000]
/ ontrialbegin = [if (values.N==3) values.mytrialduration = 2000]
...
/ trialduration = values.mytrialduration
...
</trial>

Thank you very much for your kind help! I solved all my problems now.

Thank you! Have a good night!

Have a nice evening, too!

Hello, I just got new questions.... 
I'm trying to use different key stimuli under different durations (500ms, 1000ms, 2000ms), do you know how to define N=1,2,3 to stand for different key stimuli? For example, under N=1 and duration=500ms, the key stimuli are some numbers; Under N=2 and duration=1000ms, the key stimuli are simple equations; Under N=3 and duration=2000ms, the key stimuli are complex equations.
Thank you very much!

Then you need to set up e.g. three <list>s, each representing the items applicable to the N-level.

Suppose you have

<item shapes>
/ 1 = "N1_1.gif"
/ 2 = "N1_2.gif"
/ 3 = "N1_3.gif"

/ 4 = "N2_1.gif"
/ 5 = "N2_2.gif"
/ 6 = "N2_3.gif"

/ 7 = "N3_1.gif"
/ 8 = "N3_2.gif"
/ 9 = "N3_3.gif"
</item>

i.e., three items per N-level (1-3 for N=1; 4-6 for N=2; 7-9 for N=3). Then you need

<list n1notargetlist>
/ items = (1,2,3)
/ not = (values.currenttarget)
/ select = replace
</list>

<list n2notargetlist>
/ items = (4,5,6)
/ not = (values.currenttarget)
/ select = replace
</list>

<list n3notargetlist>
/ items = (7,8,9)
/ not = (values.currenttarget)
/ select = replace
</list>

with

<values>
...
/ notargetitem = 1
...
</values>

<picture nontargetshape>
/ items = shapes
/ select = values.notargetitem
...
</picture>

and

<trial nontarget>
/ ontrialbegin = [if (values.N==1) {values.mytrialduration = 500; values.notargetitem=list.n1notargetlist.nextvalue}]
/ ontrialbegin = [if (values.N==2) values.mytrialduration = 1000; values.notargetitem=list.n2notargetlist.nextvalue}]
/ ontrialbegin = [if (values.N==3) values.mytrialduration = 2000; values.notargetitem=list.n2notargetlist.nextvalue}]
...
/ trialduration = values.mytrialduration
...
</trial>

You need to adapt the target-logic analogously.

Finally, I would *strongly* recommend you first work through the original / unchanged script until you sufficiently understand how it works (pay attention to the comments throughout). That will make it easier for you to adapt it to your needs / modify it.